<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>用typeof查看数据类型</title>
    <style>
        pre {
            color: green;
            padding: 10px 15px;
            background: #f0f0f0;
            border: 1px dotted #333;
            font: 12px/1.5 Courier New;
        }

        span {
            color: #999;
        }
    </style>
</head>

<body>
    <pre>
&lt;script type="text/javascript"&gt;
    alert(typeof 12345);	<span>//输出number</span>
    alert(typeof "abc");	<span>//输出string</span>
    alert(typeof document);	<span>//输出object</span>
&lt;/script&gt;
</pre>

    <pre>查看数据类型</pre>
    <script>
        alert('typeof 12345:' + typeof 12345 + '\n' + 'typeof abc:' + typeof 'abc' + '\n' + 'typeof document:' +
            typeof document)
    </script>
</body>

</html>